World Library  
Flag as Inappropriate
Email this Article

Clathrate compound

Article Id: WHEBN0001255740
Reproduction Date:

Title: Clathrate compound  
Author: World Heritage Encyclopedia
Language: English
Subject: Methane clathrate, Clathrates, Clathrate hydrate, Climate change in popular culture, Clathrate gun hypothesis
Collection:
Publisher: World Heritage Encyclopedia
Publication
Date:
 

Clathrate compound

A clathrate is a chemical substance consisting of a lattice that traps or contains molecules. The word clathrate is derived from the Latin clatratus meaning with bars or a lattice.[1] Traditionally, clathrate compounds are polymeric and completely envelop the guest molecule, but in modern usage clathrates also include host-guest complexes and inclusion compounds.[2] According to IUPAC, clathrates are "Inclusion compounds in which the guest molecule is in a cage formed by the host molecule or by a lattice of host molecules."[3]

Structure of the 3:1 inclusion complex of urea and 1,6-dichlorohexane. The framework is composed of molecules of urea that are linked by hydrogen bonds, leaving approximately hexagonal channels into which align the molecules of the chlorocarbon. Color scheme: oxygen is red, nitrogen is blue, chlorine is green.[4]

Contents

  • Occurrence and scope 1
  • History 2
  • Related materials 3
  • References 4

Occurrence and scope

Traditionally clathrate compounds refer to zeolites. The natural silica clathrate mineral, chibaite was recently described from Japan.

Many clathrates are derived from an organic hydrogen-bonded frameworks. These frameworks are prepared from molecules that "self-associate" by multiple hydrogen-bonding interactions. The most famous clathrates are methane clathrates where the hydrogen-bonded framework is contributed by water and the guest molecules are methane. Large amounts of methane naturally frozen in this form exist both in permafrost formations and under the ocean sea-bed.[5] Other hydrogen-bonded networks are derived from hydroquinone, urea, and thiourea. A much studied host molecule is Dianin's compound.

Space filling model of β-cyclodextrin, a host that forms clathrate complexes by inserting the guest into the "donut hole."

Hofmann compounds are Metal organic frameworks (MOFs) form clathrates.

Example of MOF-5, the cavity for the guests is indicated by the yellow sphere.

Photolytically-sensitive caged compounds have been examined as containers for releasing a drug or reagent.[6]

History

Clathrate hydrates were discovered in 1810 by Humphry Davy.[7] Clathrates were studied by P. Pfeiffer in 1927 and in 1930, E. Hertel defined "molecular compounds" as substances decomposed into individual components following the mass action law in solution or gas state. In 1945, H. M. Powell analyzed the crystal structure of these compounds and named them clathrates.

Related materials

Inclusion compounds are often molecules, whereas clathrates are typically polymeric. Intercalation compounds are not 3-dimensional, unlike clathrate compounds.

References

  1. ^ Latin dictionary
  2. ^ a b J. L. Atwood "Inclusion Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2012, Wiley-VCH, Weinheim. doi:10.1002/14356007.a14_119
  3. ^ http://goldbook.iupac.org/C01097.html
  4. ^ Hollingsworth, U.Werner-Zwanziger; Brown, J.D.Chaney; Huffman, K.D.M.Harris (1999). "Spring-Loading at the Molecular Level:  Relaxation of Guest-Induced Strain in Channel Inclusion Compounds". J. Am. Chem. Soc 121: 9732.  
  5. ^ Pearce, Fred (27 June 2009). "Ice on fire: The next fossil fuel". New Scientist. pp. 30–33. Retrieved 2009-07-05. 
  6. ^ Ellis-Davies, Graham C. R. (July 2007). "Caged compounds: photorelease technology for control of cellular chemistry and physiology". Nature Methods 4 (8): 619–28.  
  7. ^ Ellen Thomas (November 2004). "Clathrates: little known components of the global carbon cycle". Wesleyan University. Retrieved 13 December 2007. 
This article was sourced from Creative Commons Attribution-ShareAlike License; additional terms may apply. World Heritage Encyclopedia content is assembled from numerous content providers, Open Access Publishing, and in compliance with The Fair Access to Science and Technology Research Act (FASTR), Wikimedia Foundation, Inc., Public Library of Science, The Encyclopedia of Life, Open Book Publishers (OBP), PubMed, U.S. National Library of Medicine, National Center for Biotechnology Information, U.S. National Library of Medicine, National Institutes of Health (NIH), U.S. Department of Health & Human Services, and USA.gov, which sources content from all federal, state, local, tribal, and territorial government publication portals (.gov, .mil, .edu). Funding for USA.gov and content contributors is made possible from the U.S. Congress, E-Government Act of 2002.
 
Crowd sourced content that is contributed to World Heritage Encyclopedia is peer reviewed and edited by our editorial staff to ensure quality scholarly research articles.
 
By using this site, you agree to the Terms of Use and Privacy Policy. World Heritage Encyclopedia™ is a registered trademark of the World Public Library Association, a non-profit organization.
 


Copyright © World Library Foundation. All rights reserved. eBooks from Project Gutenberg are sponsored by the World Library Foundation,
a 501c(4) Member's Support Non-Profit Organization, and is NOT affiliated with any governmental agency or department.